Flashing Snowman NoveltyNo, it's snow joke - "you'll tide" yourself over the Christmas holidays with our simple electronic novelty, which adds a sparkle to the humblest festive decorations. An ideal Starter project which uses a simple op-amp based oscillator circuit to drive a number of l.e.d.s in anti-phase. Safe, battery operated low cost design, you can make your own indoor snowman using expanded polystyrene tiles. Just the thing for happy holidays.
Vehicle "Frost Box"This highly effective circuit, produced by an automotive electronics designer, helps warn of the possibility of black ice. It is based on a diode voltage drop detector and has a simple coloured l.e.d. signal which helps give advance warning of possible sub-zero temperatures outside the vehicle.
Teach-In 2000 - 3Our educational electronics series continues with basic resistive experiments and Ohm's Law, utilising our free interactive software. Join us in our practical experiments using potentiometers and light-dependent resistors.
Scratch Blanker
This highly-effective filter circuit will remove "scratch" clicks from audio tracks of vinyl LP records. It detects the presence of a scratch in the playback and blanks out the offending noise for a few milliseconds - just enought to suppress the scratch and enhancing the listener's enjoyment of the sound track.
In the March 2000 issue (P. 202), we said that the MN3004 delay line and the MN3101 clock generator i.c.s are no longer produced and had been delisted by Maplin. We suggested Sky Electronics (Tel. 020 8450 0995).
We present an easy-to-construct closed loop burglar alarms system that is readily extendable. It's also ideal as a secondary back-up system. It features auto alarm switch off, is easily expanded and has a built-in test facility.
Also in this issue - New Technology Update looks at SAW devices, Practically Speaking offers a novice's guide to mains power projects and Circuit Surgery examines some aspects of basic transistor amplifiers and more on op.amps.